Landing: 9f3003fe7223

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Project / Subsystem

gcc / gcc

Date

2026-07-03

Author

Richard Biener

Commit

9f3003fe7223765ea9ba285a1edecb15f6b5cb65

Source

github

Perf win

Breaking

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All attributes

project: gcc
subsystem: gcc
patch_id: —
commit_hash: 9f3003fe7223765ea9ba285a1edecb15f6b5cb65
source_type: github
headline: Make BB SLP costing more verbose
tldr: SLP vectorization profitability decisions are now more detailed for debugging.
author: Richard Biener
outcome: committed
performance_win: false
breaking_change: false
series_id: —
series_parts: []
tags: • optimization
• vectorization
• debugging
discussion_id_link: —
bugzilla_pr: —
url: https://github.com/gcc-mirror/gcc/commit/9f3003fe7223765ea9ba285a1edecb15f6b5cb65
date: 2026-07-03T00:00:00.000Z

The cost analysis for Superword-Level Parallelism (SLP) vectorization has been enhanced to provide more detailed debugging information. When SLP vectorization is deemed unprofitable for a basic block, the compiler now additionally dumps the costs associated with parts of the SLP graph that relate to other loops. It also outputs markers indicating the start of scalar and vector portions, aiding in the diagnosis of vectorization failures.